1. Which of the following dislocation can glide but not climb?
a) Screw dislocation
b) Edge dislocation
c) Jog dislocation
d) Mixed dislocation
Explanation: Screw dislocation can only glide in a crystal lattice along the helical path while edge dislocations can glide and climb as there is an extra plane of atom present
2. What are the dislocation in which the line direction and Burgers vector are neither perpendicular nor parallel?
a) Screw dislocation
b) Edge dislocation
c) Jog dislocation
d) Mixed dislocation
Explanation: Mixed dislocation are dislocation consisting of both screw and edge dislocation character where in screw dislocation the line direction and burger vector are parallel and for edge dislocation it is perpendicular. Therefore, the angle between line direction and Burgers vector is neither perpendicular nor parallel.
3. Which of the following can be theoretical shear stress produced in metals? ( GPa stands for Giga pascal)
a) 10 GPa
b) 32 GPa
c) 2 GPa
d) 50 GPa
Explanation: The theoretical shear stress is in the range of 3 Gpa to 30 GPa. 10GPa is the only option which lies within that range while 32 GPa, 2 GPa and 50 GPa are beyond the range in which the theoretical shear stress can lie for pure metal
4. Annealing twins which are found in metal have which type of crystal structure?
a) BCC
b) FCC
c) HCP
d) HCP and BCC
Explanation: Annealing twins are predominantly found in Face-Centered Cubic structure (FCC) metals.
5. At room temperature what is an approximate order of vibration frequency in vibration per second?
a) 1013
b) 1010
c) 104
d) 107
Explanation: Since amplitude vibration is few thousands of nanometre at room temperature. The frequency of the periodic motion is known as a vibration frequency.
6. In polymeric material the surface of which type of layer is considered to be an interfacial defect?
a) Chain ends
b) Short side branches
c) Main chain unit
d) Chain folded layer
Explanation: Chain folded layers create/ are boundaries between two crystalline regions which results in the interfacial defect.
7. Which type of boundary exists in multiphase materials across which there is a sudden change in physical/chemical properties?
a) Phase boundary
b) Chain folded layer
c) Domain wall
d) Grain boundary
Explanation: Chain folded layers are boundaries in case of polymeric materials. Domain wall deals with ferromagnetic and ferromagnetic materials and multiphase deals with phase boundary.
8. What is the density of polycrystalline specimen virtually identical to?
a) Singe crystal of different material
b) Single crystal of same material
c) Different crystal of different material
d) Different crystal of same material
Explanation: Single crystal of same material will have the same crystalline structure so their density will be identical
9. Which type of boundary causes a constant angle of tilt between lattice planes of the same type in adjacent regions of the sample?
a) Twinning boundary
b) Tilt boundary
c) Grain boundary
d) Domain wall
Explanation: When a small grain boundary is formed due to tilt in the angle of orientation is called tilt boundary. A Twin Boundary happens when the crystals on either side of a plane are mirror images of each other.
10. Volume defect or bulk defects are which dimension defect?
a) 1 dimension
b) 2 dimension
c) 3 dimension
d) 4 dimension
Explanation: Volume defects are three dimensional defects. Interfacial defects are two dimensional. In short volume defect is an application of interfacial defect.